Conversion of Overhead Contact Systems Poles to Pantographs
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Conversion of Overhead Contact Systems Poles to Pantographs Luigi Di Michele, C.E.T. Peter Hrovat, P. Eng. Toronto Transit Commission Toronto Transit Commission Toronto, Ontario, Canada Toronto, Ontario, Canada Richard J. Vella, Bsc. EE. Paul F. White Toronto Transit Commission HNTB Corporation Toronto, Ontario, Canada Chelmsford, MA USA INTRODUCTION design a new streetcar in 1972. In August of 1973, TTC placed an initial order for 200 new vehicles from OTDC, The Toronto Transit commission (TTC) has a total ten prototypes of which would be designed and built by a streetcar track mileage of 81 km [51 miles], over 100 manufacturer in Switzerland called Schweizerische complex intersections and has operated streetcars with Industrie Gesellschaftbefore (SIG).The order for 10 Swiss trolley pole current collectors since it began operating in CLRV models was cut back to six in the late 1970’s to 1921. Prior Companies had used pole operation since the provide parts needed to build an experimental articulated inception of electric streetcar in August of 1892. The version of the design but only one articulated prototype more recent PCC cars used trolley poles and the overhead was built. In the meantime, the new SIG cars started to remained compatible for trolley poles. The replacement arrive in 1977 and 1978 with the UTDC cars starting in vehicles to the PCC car, known as the Canadian Light 1979. Revenue service started in September of that year. Rail Vehicle (CLRV) manufactured by Hawker-Siddeley In 1988 the first of 52 ALRV’s was entered into revenue at Thunder Bay Ontario, were equipped with trolley pole service. By 2009 they began reaching the end of their current collectors of the same type and style as the PCC useful life and the City of Toronto and the Toronto cars, being a 14 foot trolley pole with a one and one-half Transit Commission began the process of replacement. inch diameter pole butt at the end, an Ohio Brass Form-11 Light Weight two spring trolley base and Type-J Trolley The power draw requirements for both types of Harp with carbon shoe. vehicles were nearly the same being 272 kw (453 amperes) and 260 kw (433 amperes) for the CLRV and Two types of cars were purchased, double truck ARLV respectively. The collector shoes could handle this single cars CLRV (Fig. 1) and three truck, two section current value adequately without overheating or undue articulated cars ALRV (Fig. 2). The articulated version carbon wear and the trolley poles were able to negotiate was 23.164m [76.0 ft] ft long while the non-articulated the existing overhead contact system (OCS) without issue. version was 15,226m [49.95 ft] long with truck centers at 25 ft. The cars are single end and turn direction by EXISTING OVERHEAD SYSTEM accessing loops at terminal points. Overhead System Type TTC placed an initial order for 200 new vehicles from the Ontario Transit Development Corporation later The existing OCS that was in place worked named Urban Transit Development Corporation (UTDC) extremely well and the Commission wanted to retain it and with Hawker-Siddeley, embarked on a project to but determined it was not adaptable for pantograph Page 1 of 14 operation. The system was a traditional direct suspension Fiberglass rod insulators were attached to each side of the double insulated system using 1/4” and 5/16” span wire suspension piece to add insulation as span wire was steel. made up with preformed end fittings, fiberglass rod insulators used for span wire insulation at poles, with The pullover accommodated large angles for AGC span wire hanger or cap and cone hangers with 12 enhanced pullover spacing and the curve rail smoothed inch HS clamp ears to hold the trolley wire, No-Bo out the abrupt angle so the shoe could pass through it. section insulators, Type SH trolley frogs and crossover Multiple pulloffs were eliminated by this method and the pans and a 2/0 grooved alloy 80 bronze trolley wire. It curves of grand unions and wyes became more was a classic overhead contact system that functioned aesthetically pleasing as a result. very well with trolley pole current collectors, and was very easy to maintain. The Spadina line also used OCS support poles that used ornamentation, architectural enhancements and were joint use with city streetlights. Section Insulators One OCS feature unique to Toronto was the use of No-Bo section insulators with a large diode feeding the neutral section (Fig. 11). TTC standards dictate that section insulators are to be non-bridging for safety and the older No-Bo style section insulator provided this feature. Operational rules required the streetcar operators to coast through the section insulators so arcing would not occur and minimize insulator burning. The spacing of section insulators at 20 feet apart prevented regenerative section Fig. 1 bridging across a single section insulator and this arrangement was introduced with the operation of the CLRV’s due to their regeneration capability. Under normal operation, the streetcar passes through the first section insulator onto the neutral zone but receives power from the next power section through a large capacity diode. The streetcar then passes through the second section insulator into the next power section. In the event the power section in the adjacent section was dead, the car would pass through the first section insulator and as it regenerated from braking, the diode blocked the current from passing into the dead section and prevented it from becoming alive. Fig. 2 OCS Support Poles and Bracket Arms The Commission used tubular three section steel The Spadina line, which was completely rebuilt by poles of varying sizes and heights which were directly 1997, used different OCS hardware and design criteria embedded into the earth with a concrete foundation than the core system. Suspension of contact wire was with around the embedded section. As these corroded over stitch or delta configuration using a line insulator with a time, replacement was necessary and a decision was made pulley, synthetic rope and two contact wire clamps for to standardize on one type of pole, which was an extra tangent construction. heavy steel pipe of constant diameter. Three sizes were used, an 8 inch, a 10 inch and 12 inch pipe with lengths Curves used pullovers with a long clamp ear referred varying to that needed for each particular installation. The to as a curve rail having a clamp that bolted to the rail in standard poles are direct embedded in a concrete two places with greater spacing. Attached in the center of foundation. Anchor base poles are utilized in certain this was a boss for screwing a suspension piece on. This locations. was bolted onto the clamp for pulling it into alignment. Page 2 of 14 The Commission has many locations where bracket arms are used to support the trolley wire. They are typically 2 inch standard weight pipe, galvanized and attached to the pole with a pipe insulator and pole clamp. The arm uses a guy wire to support it. Some areas of the system required non-standard bracket arms for streetscape enhancement and interesting styles were used on St. Clair and Spadina Avenues. Feeder Cables Feeder cables are typically 1000 kcmil copper Fig. 3 insulated cable strung aerially on poles or in underground conduits. Feeder taps connected to the aerial cables are run to the trolley wire and connected to it with a bronze feeder ear. Underground taps rise in conduit, outside the OCS pole and run to the trolley in the same manner as the aerial taps. Cables are attached to poles with fiberglass standoff insulators attached to the pole with galvanized steel pole bands. Span Wires Span wires consist of 5/16” seven strand galvanized steel guy wire for suspensions and pulloffs, 3/8” seven strand galvanized steel guy wire for back guys and heavy Fig. 4 loads and 1/4” seven strand galvanized steel guy wire for steadying bracket arms. Typically at poles, a 5 ft. fiberglass rod strain insulator attached to the span wire to provide secondary insulation as the trolley wire is PRELIMINARY ENGINEERING attached to a line insulator which attaches to the span wire. At the bracket arms, insulators were placed in the Current Collectors span wire steady spans at the pipe. The Commission maintains double insulation at a minimum. One of the primary concerns of the Overhead Section was the compatability of the existing overhead contact Originally, span wires were terminated by serving the system with the new vehicle’s pantograph current strands around itself but this method has been replaced collector. As TTC had no experience with pantograph with Preformed End Fittings. operation, they contacted several transit agencies and conducted meetings to find out their experiences with NEW STREETCARS pantograph operations and pole to pantograph conversions. Commission line supervisors traveled to When it was decided by the Commission that new Philadelphia to meet with their counterparts and were able streetcars were needed due to the CLRV and ALRV to receive valuable information on pantograph operation streetcars would be nearing the end of their useful life, or trolley pole to pantograph conversion. Commission the Commission began searching for a manufacturer to engineers also contacted and met with consultants who build the streetcars. In 2009, it was announced that the had pole/pantograph conversion experience. Bombardier Flexity Outlook would be the replacement vehicle. Testing began in 2013 and revenue service Interestingly, the department did not want to run with started on August 31, 2014 on the 510 Spadina route. pantographs as the entire overhead network would have to be rebuilt but the new streetcars had significant current These cars are five section articulated vehicles 100 ft draw of 100% more current, well above that of the long with low floor easy access.